kernel/linux.git/include/linux/energy_model.h, branch v6.19.11

PM: EM: Fix incorrect description of the cost field in struct em_perf_state

2026-01-08T15:52:31+00:00

Due to commit 1b600da51073 ("PM: EM: Optimize em_cpu_energy() and remove division"), the logic for energy consumption calculation has been modified. The actual calculation of cost is 10 * power * max_frequency / frequency instead of power * max_frequency / frequency. Therefore, the comment for cost has been updated to reflect the correct content. Fixes: 1b600da51073 ("PM: EM: Optimize em_cpu_energy() and remove division") Signed-off-by: Yaxiong Tian Reviewed-by: Lukasz Luba [ rjw: Added Fixes: tag ] Link: https://patch.msgid.link/20251230061534.816894-1-tianyaxiong@kylinos.cn Signed-off-by: Rafael J. Wysocki

PM: EM: Assign a unique ID when creating a performance domain

2025-10-22T19:44:37+00:00

It is necessary to refer to a specific performance domain from a userspace. For example, the energy model of a particular performance domain is updated. To this end, assign a unique ID to each performance domain to address it, and manage them in a global linked list to look up a specific one by matching ID. IDA is used for ID assignment, and the mutex is used to protect the global list from concurrent access. Note that the mutex (em_pd_list_mutex) is not supposed to hold while holding em_pd_mutex to avoid ABBA deadlock. Signed-off-by: Changwoo Min Reviewed-by: Lukasz Luba Link: https://patch.msgid.link/20251020220914.320832-2-changwoo@igalia.com Signed-off-by: Rafael J. Wysocki

PM: EM: Add function for registering a PD without capacity update

2025-09-10T10:03:19+00:00

The intel_pstate driver manages CPU capacity changes itself and it does not need an update of the capacity of all CPUs in the system to be carried out after registering a PD. Moreover, in some configurations (for instance, an SMT-capable hybrid x86 system booted with nosmt in the kernel command line) the em_check_capacity_update() call at the end of em_dev_register_perf_domain() always fails and reschedules itself to run once again in 1 s, so effectively it runs in vain every 1 s forever. To address this, introduce a new variant of em_dev_register_perf_domain(), called em_dev_register_pd_no_update(), that does not invoke em_check_capacity_update(), and make intel_pstate use it instead of the original. Fixes: 7b010f9b9061 ("cpufreq: intel_pstate: EAS support for hybrid platforms") Closes: https://lore.kernel.org/linux-pm/40212796-734c-4140-8a85-854f72b8144d@panix.com/ Reported-by: Kenneth R. Crudup Tested-by: Kenneth R. Crudup Cc: 6.16+ # 6.16+ Signed-off-by: Rafael J. Wysocki

PM: EM: Introduce em_adjust_cpu_capacity()

2025-05-13T12:34:18+00:00

Add a function for updating the Energy Model for a CPU after its capacity has changed, which subsequently will be used by the intel_pstate driver. An EM_PERF_DOMAIN_ARTIFICIAL check is added to em_recalc_and_update() to prevent it from calling em_compute_costs() for an "artificial" perf domain with a NULL cb parameter which would cause it to crash. Signed-off-by: Rafael J. Wysocki Reviewed-by: Lukasz Luba Tested-by: Christian Loehle Reviewed-by: Dietmar Eggemann Link: https://patch.msgid.link/3637203.iIbC2pHGDl@rjwysocki.net

Merge tag 'pm-6.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

2025-03-25T22:00:18+00:00

Pull power management updates from Rafael Wysocki: "These are dominated by cpufreq updates which in turn are dominated by updates related to boost support in the core and drivers and amd-pstate driver optimizations. Apart from the above, there are some cpuidle updates including a rework of the most recent idle intervals handling in the venerable menu governor that leads to significant improvements in some performance benchmarks, as the governor is now more likely to predict a shorter idle duration in some cases, and there are updates of the core device power management code, mostly related to system suspend and resume, that should help to avoid potential issues arising when the drivers of devices depending on one another want to use different optimizations. There is also a usual collection of assorted fixes and cleanups, including removal of some unused code. Specifics: - Manage sysfs attributes and boost frequencies efficiently from cpufreq core to reduce boilerplate code in drivers (Viresh Kumar) - Minor cleanups to cpufreq drivers (Aaron Kling, Benjamin Schneider, Dhananjay Ugwekar, Imran Shaik, zuoqian) - Migrate some cpufreq drivers to using for_each_present_cpu() (Jacky Bai) - cpufreq-qcom-hw DT binding fixes (Krzysztof Kozlowski) - Use str_enable_disable() helper in cpufreq_online() (Lifeng Zheng) - Optimize the amd-pstate driver to avoid cases where call paths end up calling the same writes multiple times and needlessly caching variables through code reorganization, locking overhaul and tracing adjustments (Mario Limonciello, Dhananjay Ugwekar) - Make it possible to avoid enabling capacity-aware scheduling (CAS) in the intel_pstate driver and relocate a check for out-of-band (OOB) platform handling in it to make it detect OOB before checking HWP availability (Rafael Wysocki) - Fix dbs_update() to avoid inadvertent conversions of negative integer values to unsigned int which causes CPU frequency selection to be inaccurate in some cases when the "conservative" cpufreq governor is in use (Jie Zhan) - Update the handling of the most recent idle intervals in the menu cpuidle governor to prevent useful information from being discarded by it in some cases and improve the prediction accuracy (Rafael Wysocki) - Make it possible to tell the intel_idle driver to ignore its built-in table of idle states for the given processor, clean up the handling of auto-demotion disabling on Baytrail and Cherrytrail chips in it, and update its MAINTAINERS entry (David Arcari, Artem Bityutskiy, Rafael Wysocki) - Make some cpuidle drivers use for_each_present_cpu() instead of for_each_possible_cpu() during initialization to avoid issues occurring when nosmp or maxcpus=0 are used (Jacky Bai) - Clean up the Energy Model handling code somewhat (Rafael Wysocki) - Use kfree_rcu() to simplify the handling of runtime Energy Model updates (Li RongQing) - Add an entry for the Energy Model framework to MAINTAINERS as properly maintained (Lukasz Luba) - Address RCU-related sparse warnings in the Energy Model code (Rafael Wysocki) - Remove ENERGY_MODEL dependency on SMP and allow it to be selected when DEVFREQ is set without CPUFREQ so it can be used on a wider range of systems (Jeson Gao) - Unify error handling during runtime suspend and runtime resume in the core to help drivers to implement more consistent runtime PM error handling (Rafael Wysocki) - Drop a redundant check from pm_runtime_force_resume() and rearrange documentation related to __pm_runtime_disable() (Rafael Wysocki) - Rework the handling of the "smart suspend" driver flag in the PM core to avoid issues hat may occur when drivers using it depend on some other drivers and clean up the related PM core code (Rafael Wysocki, Colin Ian King) - Fix the handling of devices with the power.direct_complete flag set if device_suspend() returns an error for at least one device to avoid situations in which some of them may not be resumed (Rafael Wysocki) - Use mutex_trylock() in hibernate_compressor_param_set() to avoid a possible deadlock that may occur if the "compressor" hibernation module parameter is accessed during the registration of a new ieee80211 device (Lizhi Xu) - Suppress sleeping parent warning in device_pm_add() in the case when new children are added under a device with the power.direct_complete set after it has been processed by device_resume() (Xu Yang) - Remove needless return in three void functions related to system wakeup (Zijun Hu) - Replace deprecated kmap_atomic() with kmap_local_page() in the hibernation core code (David Reaver) - Remove unused helper functions related to system sleep (David Alan Gilbert) - Clean up s2idle_enter() so it does not lock and unlock CPU offline in vain and update comments in it (Ulf Hansson) - Clean up broken white space in dpm_wait_for_children() (Geert Uytterhoeven) - Update the cpupower utility to fix lib version-ing in it and memory leaks in error legs, remove hard-coded values, and implement CPU physical core querying (Thomas Renninger, John B. Wyatt IV, Shuah Khan, Yiwei Lin, Zhongqiu Han)" * tag 'pm-6.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (139 commits) PM: sleep: Fix bit masking operation dt-bindings: cpufreq: cpufreq-qcom-hw: Narrow properties on SDX75, SA8775p and SM8650 dt-bindings: cpufreq: cpufreq-qcom-hw: Drop redundant minItems:1 dt-bindings: cpufreq: cpufreq-qcom-hw: Add missing constraint for interrupt-names dt-bindings: cpufreq: cpufreq-qcom-hw: Add QCS8300 compatible cpufreq: Init cpufreq only for present CPUs PM: sleep: Fix handling devices with direct_complete set on errors cpuidle: Init cpuidle only for present CPUs PM: clk: Remove unused pm_clk_remove() PM: sleep: core: Fix indentation in dpm_wait_for_children() PM: s2idle: Extend comment in s2idle_enter() PM: s2idle: Drop redundant locks when entering s2idle PM: sleep: Remove unused pm_generic_ wrappers cpufreq: tegra186: Share policy per cluster cpupower: Make lib versioning scheme more obvious and fix version link PM: EM: Rework the depends on for CONFIG_ENERGY_MODEL PM: EM: Address RCU-related sparse warnings cpupower: Implement CPU physical core querying pm: cpupower: remove hard-coded topology depth values pm: cpupower: Fix cmd_monitor() error legs to free cpu_topology ...

sched/debug: Make CONFIG_SCHED_DEBUG functionality unconditional

2025-03-19T21:20:53+00:00

All the big Linux distros enable CONFIG_SCHED_DEBUG, because the various features it provides help not just with kernel development, but with system administration and user-space software development as well. Reflect this reality and enable this functionality unconditionally. Signed-off-by: Ingo Molnar Tested-by: Shrikanth Hegde Cc: Peter Zijlstra Cc: Juri Lelli Cc: Vincent Guittot Cc: Dietmar Eggemann Cc: Steven Rostedt Cc: Ben Segall Cc: Mel Gorman Cc: Valentin Schneider Cc: Linus Torvalds Link: https://lore.kernel.org/r/20250317104257.3496611-4-mingo@kernel.org

PM: EM: Address RCU-related sparse warnings

2025-03-07T14:21:16+00:00

The usage of __rcu in the Energy Model code is quite inconsistent which causes the following sparse warnings to trigger: kernel/power/energy_model.c:169:15: warning: incorrect type in assignment (different address spaces) kernel/power/energy_model.c:169:15: expected struct em_perf_table [noderef] __rcu *table kernel/power/energy_model.c:169:15: got struct em_perf_table * kernel/power/energy_model.c:171:9: warning: incorrect type in argument 1 (different address spaces) kernel/power/energy_model.c:171:9: expected struct callback_head *head kernel/power/energy_model.c:171:9: got struct callback_head [noderef] __rcu * kernel/power/energy_model.c:171:9: warning: cast removes address space '__rcu' of expression kernel/power/energy_model.c:182:19: warning: incorrect type in argument 1 (different address spaces) kernel/power/energy_model.c:182:19: expected struct kref *kref kernel/power/energy_model.c:182:19: got struct kref [noderef] __rcu * kernel/power/energy_model.c:200:15: warning: incorrect type in assignment (different address spaces) kernel/power/energy_model.c:200:15: expected struct em_perf_table [noderef] __rcu *table kernel/power/energy_model.c:200:15: got void *[assigned] _res kernel/power/energy_model.c:204:20: warning: incorrect type in argument 1 (different address spaces) kernel/power/energy_model.c:204:20: expected struct kref *kref kernel/power/energy_model.c:204:20: got struct kref [noderef] __rcu * kernel/power/energy_model.c:320:19: warning: incorrect type in argument 1 (different address spaces) kernel/power/energy_model.c:320:19: expected struct kref *kref kernel/power/energy_model.c:320:19: got struct kref [noderef] __rcu * kernel/power/energy_model.c:325:45: warning: incorrect type in argument 2 (different address spaces) kernel/power/energy_model.c:325:45: expected struct em_perf_state *table kernel/power/energy_model.c:325:45: got struct em_perf_state [noderef] __rcu * kernel/power/energy_model.c:425:45: warning: incorrect type in argument 3 (different address spaces) kernel/power/energy_model.c:425:45: expected struct em_perf_state *table kernel/power/energy_model.c:425:45: got struct em_perf_state [noderef] __rcu * kernel/power/energy_model.c:442:15: warning: incorrect type in argument 1 (different address spaces) kernel/power/energy_model.c:442:15: expected void const *objp kernel/power/energy_model.c:442:15: got struct em_perf_table [noderef] __rcu *[assigned] em_table kernel/power/energy_model.c:626:55: warning: incorrect type in argument 2 (different address spaces) kernel/power/energy_model.c:626:55: expected struct em_perf_state *table kernel/power/energy_model.c:626:55: got struct em_perf_state [noderef] __rcu * kernel/power/energy_model.c:681:16: warning: incorrect type in assignment (different address spaces) kernel/power/energy_model.c:681:16: expected struct em_perf_state *new_ps kernel/power/energy_model.c:681:16: got struct em_perf_state [noderef] __rcu * kernel/power/energy_model.c:699:37: warning: incorrect type in argument 2 (different address spaces) kernel/power/energy_model.c:699:37: expected struct em_perf_state *table kernel/power/energy_model.c:699:37: got struct em_perf_state [noderef] __rcu * kernel/power/energy_model.c:733:38: warning: incorrect type in argument 3 (different address spaces) kernel/power/energy_model.c:733:38: expected struct em_perf_state *table kernel/power/energy_model.c:733:38: got struct em_perf_state [noderef] __rcu * kernel/power/energy_model.c:855:53: warning: dereference of noderef expression kernel/power/energy_model.c:864:32: warning: dereference of noderef expression This is because the __rcu annotation for sparse is only applicable to pointers that need rcu_dereference() or equivalent for protection, which basically means pointers assigned with rcu_assign_pointer(). Make all of the above sparse warnings go away by cleaning up the usage of __rcu and using rcu_dereference_protected() where applicable. Cc: All applicable Signed-off-by: Rafael J. Wysocki Reviewed-by: Lukasz Luba Link: https://patch.msgid.link/5885405.DvuYhMxLoT@rjwysocki.net

PM: EM: Consify two parameters of em_dev_register_perf_domain()

2025-03-06T20:23:29+00:00

Notice that em_dev_register_perf_domain() and the functions called by it do not update objects pointed to by its cb and cpus parameters, so the const modifier can be added to them. This allows the return value of cpumask_of() or a pointer to a struct em_data_callback declared as const to be passed to em_dev_register_perf_domain() directly without explicit type casting which is rather handy. No intentional functional impact. Signed-off-by: Rafael J. Wysocki Reviewed-by: Lukasz Luba Link: https://patch.msgid.link/4648962.LvFx2qVVIh@rjwysocki.net

PM: EM: Move sched domains rebuild function from schedutil to EM

2024-12-18T19:32:13+00:00

Function sugov_eas_rebuild_sd() defined in the schedutil cpufreq governor implements generic functionality that may be useful in other places. In particular, there is a plan to use it in the intel_pstate driver in the future. For this reason, move it from schedutil to the energy model code and rename it to em_rebuild_sched_domains(). This also helps to get rid of some #ifdeffery in schedutil which is a plus. No intentional functional impact. Signed-off-by: Rafael J. Wysocki Reviewed-by: Christian Loehle

PM: EM: Add min/max available performance state limits

2024-11-04T22:00:47+00:00

On some devices there are HW dependencies for shared frequency and voltage between devices. It will impact Energy Aware Scheduler (EAS) decision, where CPUs share the voltage & frequency domain with other CPUs or devices e.g. - Mid CPUs + Big CPU - Little CPU + L3 cache in DSU - some other device + Little CPUs Detailed explanation of one example: When the L3 cache frequency is increased, the affected Little CPUs might run at higher voltage and frequency. That higher voltage causes higher CPU power and thus more energy is used for running the tasks. This is important for background running tasks, which try to run on energy efficient CPUs. Therefore, add performance state limits which are applied for the device (in this case CPU). This is important on SoCs with HW dependencies mentioned above so that the Energy Aware Scheduler (EAS) does not use performance states outside the valid min-max range for energy calculation. Signed-off-by: Lukasz Luba Link: https://patch.msgid.link/20241030164126.1263793-2-lukasz.luba@arm.com Signed-off-by: Rafael J. Wysocki